A type of entrance foot mat that has become increasingly popular in the nearly twenty years since it was first introduced is one composed of elongated rail members joined together in side-by-side parallel relation by a coupling arrangement that allows the mat to be rolled up. As far as the present applicant is aware, the first mat of this type to be marketed widely was introduced in the early 1970's by Construction Specialties, Inc. ("C/S"), the assignee of the present invention, under the trademark "Pedimat.RTM.." The first version of the "Pedimat.RTM." foot mat, which is disclosed in U.S. Pat. No. 3,808,628 (Betts, May 7, 1974), comprised extruded aluminum rails joined by flexible strips that ran continuously crosswise of the rails and were joined to the rails by reception in slots in dependant side flanges of the rails having edge tabs that were crimped into engagement with the strips. The rails were spaced apart to provide gaps between adjacent rails into which dirt and water removed by the tread surfaces of the rails, which were strips of carpet, from the footwear of persons who walked across the mat could collect. Periodic cleaning of the mat and the floor under it was facilitated by rolling up the mat. The mat served its purpose of removing dirt and water very well, and the use of carpet as the tread surface made the mat aesthetically attractive. The only shortcoming of the original "Pedimat.RTM." was a lack of durability--the flexible strips that held the rails together often tore, causing the mat to gradually break up, and the rails were sometimes bent in between the rubber strips under unusually heavy loads.
In 1975, C/S introduced a new version of the "Pedimat.RTM." entrance foot mat, which is disclosed in U.S. Pat. No. 4,029,834 (Bartlett, Jun. 14, 1977) and is still being marketed. In that version, elongated extruded aluminum rails are joined together side-by-side by in a hinge-like fashion by longitudinally continuous ball and socket coupling arrangements that are integral with the rails; a ball on one rail is received in a socket on an adjacent rail. The ball portions of the rails ar joined to the tread portions by a web portion that has holes or slots through which dirt and water from the footwear of persons who walk across the mat fall to the floor under the mat. The present "Pedimat.RTM." foot mats come in three styles, one with a carpet tread member, another with a vinyl tread member and the third with a grit tread member. The tread members are inserts in an extruded rail member that is used in all three versions.
Variations of the "Pedimat.RTM." mats have been proposed, and some of the variations have been commercialized. The following U.S. patents describe and show mats similar to the all aluminum "Pedimat.RTM." mat product:
U.S. Pat. No. Re. 32,061 (Ellingson, Jr., Jan. 7, 1986)--extruded aluminum rails having sockets along each side joined by extruded aluminum hinge members of a "dogbone" cross section; PA1 U.S. Pat. No. 4,568,587 (Balzer, Feb. 4, 1986)--extruded aluminum rails with sockets along each side joined by coupling members of a flexible, extruded polymeric material, such a polyvinyl chloride, that enable the mat to be rolled up by bending of the hinge members; PA1 U.S. Pat. No. 4,877,672 (Shreiner, Oct. 31, 1989)--rail members tri-extruded from soft and hard polymeric materials, joined by integral balls and sockets and having living hinges formed in web portions by which the ball portions are joined to the tread portions of the rails. (C/S markets this product at the present time under the trademark "Treadline.RTM."). PA1 U.S. Pat. No. 4,590,110 (Arens, May 20, 1986)--brush-like tread members received in metal pans that are in turn inserted into rail members of a polymeric material, which are coupled together by metal coupling members.
Although roll-up entrance mats that include rail members or hinge members of polymeric materials are attractive and usually less expensive than all-aluminum mats, the all-aluminum mats are more durable and are considered by some people to be more attractive, because the aluminum provides a decorative accent. On the other hand, the all aluminum mats tend to rattle when walked across due to the metal-to-metal contact between the balls and sockets and some looseness in the ball and socket couplings, the looseness being inevitable because the fit between the balls and sockets has to be such that the rails can be slid together at assembly and the couplings can rotate.